Keilim 23:4

The bier, pillow and mattress of a corpse are susceptible to midras impurity. Rabbi Yosi says that a bridal chair, a birthing stool and the chair on which a launderer presses clothes are not susceptible to impurity as seats.

Keilim 23:5

A fishing net is susceptible to ritual impurity because of its bag (a cloth receptacle at the bottom). Nets, snares, pit bird traps, lassos and dam traps are susceptible to impurity; fish traps, box bird traps and cages are insusceptible.